about draft-ietf-v6ops-cpe-simple-security-07

[Iljitsch van Beijnum <iljitsch@muada.com>]

[to v6ops and shim6, prune as necessary]

   R11: Filter state records for generic upper-layer transport  
protocols
   MUST NOT be deleted or recycled until an idle timer not less than  
two
   minutes has expired without having forwarded a packet matching the
   state in some configurable amount of time.  By DEFAULT, the idle
   timer for such state records is five minutes.

That seems rather short: new transports would now have to send  
keepalives every 1.75 minutes. I'd say that a timeout MUST be at least  
11 minutes and preferably 124 minutes, like TCP.

If the timers for unknown transports are compatible with those needed  
for SCTP and DCCP then implementers can forego handling those  
explicitly but they'll still work.

3.2.4.  6to4 Tunnels

   Typical dual-stack IPv4/IPv6 residential gateways use private IPv4
   address ranges and network address/port translation on a single IPv4
   address assigned by the service provider.  The use of private
   addresses prevents interior hosts from using 6to4 [RFC3068] tunnels.

Usually the private addresses are on the inside and a public on the  
outside (which will presumably start to change as IPv4 depletes but  
will never completely go away) so 6to4 can work just fine in those  
cases.

   The use of Level 3 Multihoming Shim
   Protocol for IPv6 (SHIM6) [I-D.ietf-shim6-proto] as a site multi-
   homing solution is not generally compatible with IPv6 simple
   security.

(Now RFC 5533.) Why? Assuming that there are two CPEs with each an ISP  
link and advertising separate address ranges, then if the host sends  
normal packets over CPE A and then when the ISP connected to CPE A  
fails, the host can send protocol 140 signaling and encapsulated data  
packets to CPE B. This should work. An optimization would be to allow  
incoming protocol 140 whenever there is communication between an  
internal and external host already, whatever the type. (Without that,  
the shim6 signaling fails when the first host initiates it and only  
succeeds if the second host initiates it soon enough after.)